The present invention generally relates to a compact and portable data processing apparatus such as a compact and portable facsimile machine, and more particularly to an improvement in a power supply system of such a compact and portable data processing apparatus.
Recently, there has been considerable activity in the development of a compact and portable facsimile machine. A compact and portable facsimile machine is designed to be used not only indoors, but also outdoors and in an automobile. Such a compact and portable facsimile machine must be suitable for various power sources.
As shown in FIG. 1A, a facsimile machine main body 1 of a facsimile machine is connected to a commercial power source adapter 2 when the facsimile machine is used indoors. The commercial power source adapter 2 is formed of an AC/DC (alternating current/direct current) converter, which generates DC power having various voltages equal to, for example, .+-.5 volts or .+-.12 volts from a commercial AC voltage. When the facsimile machine is used in an automobile, as shown in FIG. 1B, an automobile power source adapter 3 formed of a DC/DC converter is connected to the facsimile machine main body 1. The automobile power source adapter 3 has the function of converting automobile DC power into DC power having various voltages. When the facsimile machine is used outdoors, the facsimile machine main body 1 is coupled to a battery, such as a nickel cadmium battery, through a battery adapter 4. The battery adapter 4 is also formed of a DC/DC converter, which generates the necessary DC power having various voltages from the battery power source.
As described above, the conventional facsimile machine needs different adapters for different applications. This increases the production cost of facsimile machines. Further, the entire power supply system of the facsimile machine is not configured efficiently. For example, the automobile power source adapter 3 and the battery adapter 4 have the respective DC/DC converters.